/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package axil.framework.xml;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import static axil.framework.Functions.abort;
import static axil.framework.Functions.nv;


/**
 * The base class for the various factory mechanisms for creating objects being
 * deserialized from XML.
 */
abstract class XMLFactory {
	private static final Map<Class,XMLFactory> factories =
	    new ConcurrentHashMap<Class, XMLFactory>();


	static XMLFactory discover(Class type) {
		XML x = (XML)type.getAnnotation(XML.class);
		if (x == null) {
			return find(type);
		}
		if (x.name().equals("###")) {
			return new AnnotationFactory(type, x);
		}
		return find(type);
	}


	private static XMLFactory find(Class type) {
		XMLFactory factory = ConstructorFactory.from(type);
		if (factory == null) {
			factory = StaticMethodFactory.from(type);
			if (factory == null) {
				throw abort(
				    "The type does not provide XML construction " +
				    "information. Either the @XML annotation must be " +
				    "specified for the type or it must provide the " +
				    "necessary constructor method.", nv("type", type));
			}
		}
		return factory;
	}


	public static XMLFactory factory(Class type) {
		XMLFactory factory = factories.get(type);
		if (factory == null) {
			factory = discover(type);
			factories.put(type, factory);
		}
		return factory;
	}


	/**
	 * Get the name of the tag used to represent the object constructed by this
	 * factory. If no such tag is known, then an exception is thrown; the value
	 * returned is never null.
	 */
	public abstract String tag();


	/**
	 * Tell if this factory recognizes the given tag and can construct an object
	 * from it. This is only used when dealing with abstract types.
	 */
	public abstract boolean matches(String tag);


	/**
	 * Construct a new instance of the type represented by this factory object.
	 * The value returned is never null.
	 */
	public abstract <T> T construct(InputXML xml);
}
